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clang-p2996/llvm/test/CodeGen/WebAssembly/eh-lsda.ll
Heejin Ahn 77b921b870 [WebAssembly] Tidy up EH/SjLj options 
This CL is small, but the description can be a little long because I'm
trying to sum up the status quo for Emscripten/Wasm EH/SjLj options.

First, this CL adds an option for Wasm SjLj (`-wasm-enable-sjlj`), which
handles SjLj using Wasm EH. The implementation for this will be added as
a followup CL, but this adds the option first to do error checking.

This also adds an option for Wasm EH (`-wasm-enable-eh`), which has been
already implemented. Before we used `-exception-model=wasm` as the same
meaning as enabling Wasm EH, but after we add Wasm SjLj, it will be
possible to use Wasm EH instructions for Wasm SjLj while not enabling
EH, so going forward, to use Wasm EH, `opt` and `llc` will need this
option. This only affects `opt` and `llc` command lines and does not
affect Emscripten user interface.

Now we have two modes of EH (Emscripten/Wasm) and also two modes of SjLj
(also Emscripten/Wasm). The options corresponding to each of are:
- Emscripten EH: `-enable-emscripten-cxx-exceptions`
- Emscripten SjLj: `-enable-emscripten-sjlj`
- Wasm EH: `-wasm-enable-eh -exception-model=wasm`
           `-mattr=+exception-handling`
- Wasm SjLj: `-wasm-enable-sjlj -exception-model=wasm`
             `-mattr=+exception-handling`
The reason Wasm EH/SjLj's options are a little complicated are
`-exception-model` and `-mattr` are common LLVM options ane not under
our control. (`-mattr` can be omitted if it is embedded within the
bitcode file.)

And we have the following rules of the option composition:
- Emscripten EH and Wasm EH cannot be turned on at the same itme
- Emscripten SjLj and Wasm SjLj cannot be turned on at the same time
- Wasm SjLj should be used with Wasm EH

Which means we now allow these combinations:
- Emscripten EH + Emscripten SjLj: the current default in `emcc`
- Wasm EH + Emscripten SjLj:
  This is allowed, but only as an interim step in which we are testing
  Wasm EH but not yet have a working implementation of Wasm SjLj. This
  will error out (D107687) in compile time if `setjmp` is called in a
  function in which Wasm exception is used.
- Wasm EH + Wasm SjLj:
  This will be the default mode later when using Wasm EH. Currently Wasm
  SjLj implementation doesn't exist, so it doesn't work.
- Emscripten EH + Wasm SjLj will not work.

This CL moves these error checking routines to
`WebAssemblyPassConfig::addIRPasses`. Not sure if this is an ideal place
to do this, but I couldn't find elsewhere. Currently some checking is
done within LowerEmscriptenEHSjLj, but these checks only run if
LowerEmscriptenEHSjLj runs so it may not run when Wasm EH is used. This
moves that to `addIRPasses` and adds some more checks.

Currently LowerEmscriptenEHSjLj pass is responsible for Emscripten EH
and Emscripten SjLj. Wasm EH transformations are done in multiple
places, including WasmEHPrepare, LateEHPrepare, and CFGStackify. But in
the followup CL, LowerEmscriptenEHSjLj pass will be also responsible for
a part of Wasm SjLj transformation, because WasmSjLj will also be using
several Emscripten library functions, and we will be sharing more than
half of the transformation to do that between Emscripten SjLj and Wasm
SjLj.

Currently we have `-enable-emscripten-cxx-exceptions` and
`-enable-emscripten-sjlj` but these only work for `llc`, because for
`llc` we feed these options to the pass but when we run the pass using
`opt` the pass will be created with no options and the default options
will be used, which turns both Emscripten EH and Emscripten SjLj on.

Now we have one more SjLj option to care for, LowerEmscriptenEHSjLj pass
needs a finer way to control these options. This CL removes those
default parameters and make LowerEmscriptenEHSjLj pass read directly
from command line options specified. So if we only run
`opt -wasm-lower-em-ehsjlj`, currently both Emscripten EH and Emscripten
SjLj will run, but with this CL, none will run unless we additionally
pass `-enable-emscripten-cxx-exceptions` or `-enable-emscripten-sjlj`,
or both. This does not affect users; this only affects our `opt` tests
because `emcc` will not call either `opt` or `llc`. As a result of this,
our existing Emscripten EH/SjLj tests gained one or both of those
options in their `RUN` lines.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D107685
2021-08-24 17:54:39 -07:00

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; RUN: llc < %s -disable-wasm-fallthrough-return-opt -wasm-keep-registers -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling | FileCheck -allow-deprecated-dag-overlap %s
target triple = "wasm32-unknown-unknown"
@_ZTIi = external constant i8*
@_ZTIf = external constant i8*
@_ZTId = external constant i8*
; Single catch (...) does not need an exception table.
;
; try {
; may_throw();
; } catch (...) {
; }
; CHECK-LABEL: test0:
; CHECK-NOT: GCC_except_table
define void @test0() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
invoke void @may_throw()
to label %try.cont unwind label %catch.dispatch
catch.dispatch: ; preds = %entry
%0 = catchswitch within none [label %catch.start] unwind to caller
catch.start: ; preds = %catch.dispatch
%1 = catchpad within %0 [i8* null]
%2 = call i8* @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
%4 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
call void @__cxa_end_catch() [ "funclet"(token %1) ]
catchret from %1 to label %try.cont
try.cont: ; preds = %entry, %catch.start
ret void
}
; Exception table generation + shared action test.
;
; try {
; may_throw();
; } catch (int) {
; } catch (float) {
; } catch (double) {
; } catch (...) {
; }
;
; try {
; may_throw();
; } catch (double) {
; } catch (...) {
; }
;
; try {
; may_throw();
; } catch (int) {
; } catch (float) {
; }
;
; There are three landing pads. The second landing pad should share action table
; entries with the first landing pad because they end with the same sequence
; (double -> ...). But the third landing table cannot share action table entries
; with others, so it should create its own entries.
; CHECK-LABEL: test1:
; CHECK: .section .rodata.gcc_except_table,"",@
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: GCC_except_table[[START:[0-9]+]]:
; CHECK-NEXT: .Lexception0:
; CHECK-NEXT: .int8 255 # @LPStart Encoding = omit
; CHECK-NEXT: .int8 0 # @TType Encoding = absptr
; CHECK-NEXT: .uleb128 .Lttbase0-.Lttbaseref0
; CHECK-NEXT: .Lttbaseref0:
; CHECK-NEXT: .int8 1 # Call site Encoding = uleb128
; CHECK-NEXT: .uleb128 .Lcst_end0-.Lcst_begin0
; CHECK-NEXT: .Lcst_begin0:
; CHECK-NEXT: .int8 0 # >> Call Site 0 <<
; CHECK-NEXT: # On exception at call site 0
; CHECK-NEXT: .int8 7 # Action: 4
; CHECK-NEXT: .int8 1 # >> Call Site 1 <<
; CHECK-NEXT: # On exception at call site 1
; CHECK-NEXT: .int8 3 # Action: 2
; CHECK-NEXT: .int8 2 # >> Call Site 2 <<
; CHECK-NEXT: # On exception at call site 2
; CHECK-NEXT: .int8 11 # Action: 6
; CHECK-NEXT: .Lcst_end0:
; CHECK-NEXT: .int8 1 # >> Action Record 1 <<
; CHECK-NEXT: # Catch TypeInfo 1
; CHECK-NEXT: .int8 0 # No further actions
; CHECK-NEXT: .int8 2 # >> Action Record 2 <<
; CHECK-NEXT: # Catch TypeInfo 2
; CHECK-NEXT: .int8 125 # Continue to action 1
; CHECK-NEXT: .int8 3 # >> Action Record 3 <<
; CHECK-NEXT: # Catch TypeInfo 3
; CHECK-NEXT: .int8 125 # Continue to action 2
; CHECK-NEXT: .int8 4 # >> Action Record 4 <<
; CHECK-NEXT: # Catch TypeInfo 4
; CHECK-NEXT: .int8 125 # Continue to action 3
; CHECK-NEXT: .int8 3 # >> Action Record 5 <<
; CHECK-NEXT: # Catch TypeInfo 3
; CHECK-NEXT: .int8 0 # No further actions
; CHECK-NEXT: .int8 4 # >> Action Record 6 <<
; CHECK-NEXT: # Catch TypeInfo 4
; CHECK-NEXT: .int8 125 # Continue to action 5
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: # >> Catch TypeInfos <<
; CHECK-NEXT: .int32 _ZTIi # TypeInfo 4
; CHECK-NEXT: .int32 _ZTIf # TypeInfo 3
; CHECK-NEXT: .int32 _ZTId # TypeInfo 2
; CHECK-NEXT: .int32 0 # TypeInfo 1
; CHECK-NEXT: .Lttbase0:
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: .LGCC_except_table_end[[END:[0-9]+]]:
; CHECK-NEXT: .size GCC_except_table[[START]], .LGCC_except_table_end[[END]]-GCC_except_table[[START]]
define void @test1() personality i8* bitcast (i32 (...)* @__gxx_wasm_personality_v0 to i8*) {
entry:
invoke void @may_throw()
to label %try.cont unwind label %catch.dispatch
catch.dispatch: ; preds = %entry
%0 = catchswitch within none [label %catch.start] unwind to caller
catch.start: ; preds = %catch.dispatch
%1 = catchpad within %0 [i8* bitcast (i8** @_ZTIi to i8*), i8* bitcast (i8** @_ZTIf to i8*), i8* bitcast (i8** @_ZTId to i8*), i8* null]
%2 = call i8* @llvm.wasm.get.exception(token %1)
%3 = call i32 @llvm.wasm.get.ehselector(token %1)
%4 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
%matches = icmp eq i32 %3, %4
br i1 %matches, label %catch10, label %catch.fallthrough
catch10: ; preds = %catch.start
%5 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
%6 = bitcast i8* %5 to i32*
%7 = load i32, i32* %6, align 4
call void @__cxa_end_catch() [ "funclet"(token %1) ]
catchret from %1 to label %try.cont
try.cont: ; preds = %entry, %catch, %catch4, %catch7, %catch10
invoke void @may_throw()
to label %try.cont23 unwind label %catch.dispatch14
catch.dispatch14: ; preds = %try.cont
%8 = catchswitch within none [label %catch.start15] unwind to caller
catch.start15: ; preds = %catch.dispatch14
%9 = catchpad within %8 [i8* bitcast (i8** @_ZTId to i8*), i8* null]
%10 = call i8* @llvm.wasm.get.exception(token %9)
%11 = call i32 @llvm.wasm.get.ehselector(token %9)
%12 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTId to i8*))
%matches16 = icmp eq i32 %11, %12
%13 = call i8* @__cxa_begin_catch(i8* %10) [ "funclet"(token %9) ]
br i1 %matches16, label %catch20, label %catch17
catch20: ; preds = %catch.start15
%14 = bitcast i8* %13 to double*
%15 = load double, double* %14, align 8
call void @__cxa_end_catch() [ "funclet"(token %9) ]
catchret from %9 to label %try.cont23
try.cont23: ; preds = %try.cont, %catch17, %catch20
invoke void @may_throw()
to label %try.cont36 unwind label %catch.dispatch25
catch.dispatch25: ; preds = %try.cont23
%16 = catchswitch within none [label %catch.start26] unwind to caller
catch.start26: ; preds = %catch.dispatch25
%17 = catchpad within %16 [i8* bitcast (i8** @_ZTIi to i8*), i8* bitcast (i8** @_ZTIf to i8*)]
%18 = call i8* @llvm.wasm.get.exception(token %17)
%19 = call i32 @llvm.wasm.get.ehselector(token %17)
%20 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
%matches27 = icmp eq i32 %19, %20
br i1 %matches27, label %catch33, label %catch.fallthrough28
catch33: ; preds = %catch.start26
%21 = call i8* @__cxa_begin_catch(i8* %18) [ "funclet"(token %17) ]
%22 = bitcast i8* %21 to i32*
%23 = load i32, i32* %22, align 4
call void @__cxa_end_catch() [ "funclet"(token %17) ]
catchret from %17 to label %try.cont36
catch.fallthrough28: ; preds = %catch.start26
%24 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIf to i8*))
%matches29 = icmp eq i32 %19, %24
br i1 %matches29, label %catch30, label %rethrow
catch30: ; preds = %catch.fallthrough28
%25 = call i8* @__cxa_begin_catch(i8* %18) [ "funclet"(token %17) ]
%26 = bitcast i8* %25 to float*
%27 = load float, float* %26, align 4
call void @__cxa_end_catch() [ "funclet"(token %17) ]
catchret from %17 to label %try.cont36
rethrow: ; preds = %catch.fallthrough28
call void @__cxa_rethrow() [ "funclet"(token %17) ]
unreachable
try.cont36: ; preds = %try.cont23, %catch30, %catch33
ret void
catch17: ; preds = %catch.start15
call void @__cxa_end_catch() [ "funclet"(token %9) ]
catchret from %9 to label %try.cont23
catch.fallthrough: ; preds = %catch.start
%28 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIf to i8*))
%matches1 = icmp eq i32 %3, %28
br i1 %matches1, label %catch7, label %catch.fallthrough2
catch7: ; preds = %catch.fallthrough
%29 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
%30 = bitcast i8* %29 to float*
%31 = load float, float* %30, align 4
call void @__cxa_end_catch() [ "funclet"(token %1) ]
catchret from %1 to label %try.cont
catch.fallthrough2: ; preds = %catch.fallthrough
%32 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTId to i8*))
%matches3 = icmp eq i32 %3, %32
%33 = call i8* @__cxa_begin_catch(i8* %2) [ "funclet"(token %1) ]
br i1 %matches3, label %catch4, label %catch
catch4: ; preds = %catch.fallthrough2
%34 = bitcast i8* %33 to double*
%35 = load double, double* %34, align 8
call void @__cxa_end_catch() [ "funclet"(token %1) ]
catchret from %1 to label %try.cont
catch: ; preds = %catch.fallthrough2
call void @__cxa_end_catch() [ "funclet"(token %1) ]
catchret from %1 to label %try.cont
}
declare void @may_throw()
; Function Attrs: nounwind
declare i32 @llvm.eh.typeid.for(i8*) #0
; Function Attrs: nounwind
declare i8* @llvm.wasm.get.exception(token) #0
; Function Attrs: nounwind
declare i32 @llvm.wasm.get.ehselector(token) #0
declare void @__cxa_rethrow()
declare i8* @__cxa_begin_catch(i8*)
declare void @__cxa_end_catch()
declare i32 @__gxx_wasm_personality_v0(...)
attributes #0 = { nounwind }
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